Antifa isn't a real organization, it's just a bunch of disconnected groups that have recently been getting labeled as Antifa. Most don't even claim to be part of Antifa. Antifa is basically the boogeyman that Republicans made up to distract from the fact that a bunch of far right wing people were literally organizing armed pseudo-militias with the intent of overthrowing the US government. They knew these idiots stood no chance so they downplayed them and made up conspiracies about left wingers doing the same shit, and pretending like there was a serious threat from the left instead of the right.